1. Field of the Invention
This invention relates to a lock mechanism assembly having automatic and manual locking procedures for locking drawers in a cabinet, and more generally to an improved lock mechanism for fixing a slide bar in either of two positions.
2. Description of the Related Art
There are many examples of manual or automatic means for locking drawers in a cabinet. One type of cabinet for which locking drawers can be especially important is a medical supply cart. A medical supply cart commonly contains medical equipment, instruments, and supplies that are necessary for treating patients in the hospital. Security of such items can be particularly important to prevent unauthorized dispensing or use of such items.
A supply cart generally includes a housing having a plurality of drawers, shelves, and/or compartments for storing the medical equipment and supplies. The housing is typically supported by a plurality of wheels or casters so that it may be moved from its place of storage to the location of the patient. To provide security of the items contained therein, supply carts typically have a security latch mechanism for simultaneously securing all compartments of the cart in a sealed condition.
One example of a drawer closing and latching mechanism is disclosed in U.S. Pat. No. 6,511,138 to Gardner et al. As discussed in that patent, drawers which are slightly ajar are grasped by the latching mechanism, pulled fully closed, and locked shut. A latch finger engages a catch connected to the drawer and pulls the drawer closed. The finger is actuated by a crankshaft which, as it rotates, first lowers the latch finger to capture the catch, and then retracts the latch finger and with it the captured drawer. The crankshaft rotates to a position where any pull forces on the finger are nearly in line with the axis of the crankshaft and have little tendency to cause reverse rotation. The crankshaft is then retained in this position, effectively locking the drawer closed.
While prior art systems such as that disclosed in the Gardner patent are generally good for their intended purposes, the current state of the art of such conventional lock mechanisms would benefit from improvements in a number of respects. For example, there is a need for an improved lock mechanism that is smaller and simpler, with fewer parts, that is less expensive, and the operation of which is highly reliable.